Surveillance cameras are installed in stations, specific facilities, and the like, and video captured by the surveillance cameras is analyzed to perform various determination. As an example, a person or object present in a monitoring range for an unusually long time is identified as a suspicious person or object.
As a relevant technique, a behavior analysis method of tracking a specific person and analyzing his or her behavior is known. In the behavior analysis method, for example, where the specific person is present is recognized using one camera or a plurality of cameras that overlap in monitoring area, and the temporal changes of the position of the person are tracked to determine where and how long the person stayed.
A person recognition method of performing face matching to recognize a specific person from a captured image is known, too. Patent Literature (PTL) 1 describes a face image recognition device capable of a faster face image recognition process to simplify registration operation. The face image recognition device described in PTL 1 registers a frontal face image of each person to be recognized and an average face image of the person in an orientation other than the front, and matches the features of a face area extracted from video against the registered face images to recognize the face image in the video.